1. Field of the Invention
The present invention relates to a roller type one-way clutch that is used for an automatic transmission or the like and has a roller that transmits torque interposed between an inner race and an outer race. In more detail, the present invention relates to an improved roller type one-way clutch having a block bearing.
2. Description of the Related Art
A roller type one-way clutch that is one type of one-way clutches is configured to lock rotation in one way by pressing a roller to mesh with a cam surface provided on an inner peripheral surface of an outer race or an outer peripheral surface of an inner race.
Japanese Patent Application Laid-Open No. 2011-47481 discloses an example of a prior art roller type one-way clutch provided with a block bearing. In Japanese Patent Application Laid-Open No. 2011-47481, an accordion spring is allowed to bear an energizing load that can prevent a roller from coming off in a sub-assembly state. Further, there is also disclosed a roller type one-way clutch that has a gap provided between a locking convex portion of the block bearing and a concave groove of an outer race, assures a rollable distance of a roller when an entire cage rotates a distance corresponding to the gap in the circumferential direction at the time of loading predetermined torque, and has a function of transmitting torque while reducing drag torque.
Furthermore, Japanese Patent Application Laid-Open No. 2005-16555 discloses a roller type one-way clutch in which a block bearing is interposed as bearing means between an outer race member and an inner race member and a gap between a stationary member and the outer race member is set to be smaller than a gap between a rotary member and an inner race member. As a result, when an arc-shaped support reference surface provided on the outer race member is regulated and supported, positioning in the radial direction is carried out, and wear of the rotary member and others can be reduced.
However, in each of the roller type one-way clutches disclosed in Japanese Patent Application Laid-Open No. 2011-47481 and Japanese Patent Application Laid-Open No. 2005-16555, the block bearing itself produces the drag torque. Each of Japanese Patent Application Laid-Open No. 2011-47481 and Japanese Patent Application Laid-Open No. 2005-16555 still has a problem that the drag torque produced from the block bearing cannot be sufficiently reduced.